1 Lady Elliot Island eco-resort’s transition to 100 percent renewable energy Dr Steve Carter 1,2 Mr Robert Thomas 1 Mr Peter Gash OAM 1 1 Lady Elliot Island Eco-Resort, PO Box 348, Runaway Bay, Qld 4216. 2 University of Tasmania, Private Bag 37, Hobart, Tas 7001. * Corresponding author emails: [email protected]and [email protected]Griffith Institute for Tourism Research Report No 16 January 2020 ISSN 2203-4862 (Print) ISSN 2203-4870 (Online) ISBN 978-1-925455-96-0 Griffith University, Queensland, Australia
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Lady Elliot Island eco-resort’s transition to · 2020-01-28 · 1 Lady Elliot Island eco-resort’s transition to100 percent renewable energy Dr Steve Carter1,2 Mr Robert Thomas1
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Lady Elliot Island eco-resort’s transition to
100 percent renewable energy
Dr Steve Carter1,2
Mr Robert Thomas1
Mr Peter Gash OAM1
1 Lady Elliot Island Eco-Resort, PO Box 348, Runaway Bay, Qld 4216.
2 University of Tasmania, Private Bag 37, Hobart, Tas 7001.
Power is an essential service, so the concern that the LEI team would have difficulty operating
the HSP station was a significant barrier to change which resurfaced soon after the HSP station
was commissioned because a mistake in operating the station led to two of the eco-resort’s three
generators being damaged beyond repair. Only one generator was needed to help the solar
panels meet the power needs of the eco-resort, but the eco-resort had suddenly lost the ability
to close down the solar panels and return to operating generators alone.
iii) Practical knowledge
An issue related to the complexity of an HSP station was lack of practical knowledge about its
operation on the part of both the LEI team and suppliers. The LEI team realised they would need
to overcome a learning curve before they could operate the new station with confidence. It was
also clear that some people promoting the benefits of an HSP station did not have much
experience of operating equipment in the harsh environmental conditions of a remote coral cay.
It is important that people who operate equipment in a remote location learn how the equipment
works at a hands-on level and be able to service the equipment themselves to the extent possible,
thereby avoiding unnecessary reliance on specialist suppliers. The LEI team had learned this
lesson in other areas, including operation of a new wastewater treatment plant that took a lot of
effort before it achieved ongoing good performance. This experience helped the team to
overcome the concern that they would find themselves out of their depth. They set out on the
learning curve having faith in themselves, believing they would succeed in gaining the practical
knowledge necessary to ensure a transition to renewable energy. Believing something is possible
improves the chance of success. A can-do attitude is essential to changing to a new way of doing
things.
iv) Specialist support
Equipment operating on a barrier reef island often needs significant maintenance, due to
corrosion by the salty marine air, problems caused by high air temperature and humidity, extreme
weather events (including cyclones), and damage from bird faeces since the island is home to
thousands of birds. Inevitably some issues require support from off-island specialists. In addition,
spare parts need to be readily available, a potential problem given that many components of the
HSP station would be provided by overseas suppliers.
These concerns were barriers to change, rather than outcomes of a learning experience,
because they were recognised issues when the eco-resort was considering making the transition
to renewable energy, since they also apply to other equipment operated by the eco-resort, such
as its wastewater treatment and desalination plants. The eco-resort’s experience is that some
suppliers have difficulty accepting that their equipment isn’t performing according to expectations
because they don’t appreciate the harsh environmental conditions associated with a coral cay.
It is also common for suppliers to underestimate the cost of providing follow-up support for
equipment operating on a remote island.
The eco-resort employed a number of strategies to help overcome these barriers to change, in
addition to the measures outlined above.
• The energy demand reduction initiatives are described in Section 3. Perhaps one of the
most important initiatives was the recognition that surplus freshwater and compressed air
(for SCUBA tanks) produced during periods of peak solar power generation could act as
additional batteries. Notton (2015) also recognised the importance of energy storage in
the context of renewable energy systems for islands.
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• The eco-resort took small steps. Its transition to renewable energy has taken 11 years to
date, with new solar panel arrays added on a regular basis. This step-by-step strategy has
minimised the consequences of problems and has facilitated a series of initiatives to
improve the HSP station’s performance.
• The eco-resort installed a number of separate and relatively small solar panel arrays
instead of a fewer number of larger arrays, to minimise the consequences in the event an
array experienced a problem and had to be taken off line for some reason.
• Knowledge sharing with others is very helpful and a two-way street. LEI management
reached out to others to discuss the eco-resort’s efforts to transition to renewable energy
and has been contacted by others seeking to learn from the eco-resort. Indeed, this paper
is deliberately written in a way that the authors hope will make it readable to operators of
other facilities in remote locations.
• The LEI team invested in making several of their people responsible for leading the
transition. Their goals were to know the suppliers, understand how to install and operate
solar panel arrays, battery banks and the control system, seek ways to improve operation
of the HSP station, and plan the installation of new infrastructure. These people were also
in charge of the ongoing energy demand reduction work.
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5. Renewable energy infrastructure
Figure 3 shows the key components of a hybrid solar power station, including the multi-cluster
control box that integrates the components into a cohesive system.
Figure 3. The key components of a hybrid solar power station.
A solar power installation uses the photovoltaic cells in an array of solar panels to produce a
Direct Current (DC). This can be used to power DC electrical loads, perhaps with a voltage
regulator, or an inverter can convert the DC to single-phase Alternating Current (AC) which can
power small AC electrical loads, typically less than 1 kW. Three-phase AC is necessary for larger
electric loads and initially this was produced using three sets of solar panels, each served by an
inverter. Now the HSP station feeds the output from three sets of solar panels to a single inverter
able to output three-phase AC.
Battery banks provide energy storage capacity. If the incoming power is AC, then an inverter is
needed to convert the power to DC. Stored energy is released as DC, and as with the solar
power this can either be used to power DC electrical loads or inverters can convert the DC to
either single-phase or three-phase AC.
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If the available solar power is more than the eco-resort needs at that particular time, then the
surplus power can be used to charge the batteries. If the eco-resort needs more power than is
available from the solar panel arrays, then it can be provided by the battery banks.
Figure 4 shows photographs of the HSP station soon after it was commissioned in 2008. It is an
open-sided east-west hardwood timber facility that has little environmental impact, resting on
simple concrete bearers that have not damaged the underlying coral cay. The HSP station is
designed to withstand cyclone-level winds. Worst-case wind loading is when winds are from the
south, but that side of the HSP station is a vertical wall, the solar panel array tilts towards the
north, and the structure weighs over 80 tonnes so southerly wind loading is not able to exert an
upward force on the solar panel array.
Figure 4. Clockwise from top left. The HSP station soon after it was commissioned in 2008,
with the green diesel generator just visible under the solar panels; lead-acid battery banks;
the three inverters (red boxes) serving the solar panels, and three inverters (yellow boxes)
serving one of the battery banks; and the inside of the multi-cluster control box.
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The HSP station components have changed over time, as discussed below, but in 2008 were as
follows:
• Solar panels. 96 x 1.5 m2 Kyocera solar panels. The panels each produce 205 W at 1,000 W/m2 of solar radiation*, and together generate ~20 kW of power under these conditions.
• Inverters. The solar panels are served by three SMA Sunny Mini Central 7000TL inverters, each producing single phase AC power. Each battery bank is served by three SMA Sunny Island 5048 inverters (one master, and two slaves), which each produce single phase AC power from the batteries and can also charge the batteries.
• Generator. An 80 kVA Nippon Sharyo diesel generator, with a DD-6BG1T engine serving an NEA-7504 alternator that produces 56 kW (at 1500 rpm) of three phase AC power.
• Batteries. Two x 24 Sonnenschein (Exide) A602/3500 lead acid battery banks.
• Control system. An SMA MC12 multi-cluster box. This control system combines the single-phase power feeds from the battery bank inverters, and from the solar panel inverters, into 3-phase 415V AC power. Power from the generator is also managed by the multi-cluster box.
By 2010, the HSP station and energy reduction initiatives together had reduced the eco-resort’s
diesel fuel usage by 400 litres per day. Diesel fuel in 2010 cost $1.40 per litre but the cost of
transporting fuel to the island by barge added $0.50 per litre. A detailed calculation of the pay-
back period would include the cost of implementing the energy reduction initiatives, offset by the
reduced cost of upgrading the fuel handling and storage systems, but at first pass the eco-resort
estimated that it was saving nearly $250,000 per year by 2010, and that the HSP station paid for
itself in just under three years.
Importantly, the cost of fuel does not include a Federal Government subsidy of 20 to 30 cents
per litre, which the eco-resort qualifies for (along with airlines, haulage companies etc.). Without
the subsidy the eco-resort would have been saving more, making the transition to renewable
energy even more attractive.
After commissioning the HSP station, the eco-resort has steadily increased and improved its
renewable power infrastructure. Figure 5 shows the eco-resort in late 2019 and Table 1 lists the
solar panel arrays installed through to late 2019. Table 1 shows that the eco-resort in late 2019
had a total of 165 kW of generating power (at 1,000 W/m2 of solar radiation*), which equates to
a 220 kVA diesel generator with a power factor of 0.8 and a typical fuel usage rate of 40 litres/hour
under load.
Batteries have been the worst performing component of the renewable energy infrastructure.
Table 2 summarises their history and Table 3 lists the nine battery banks serving the eco-resort
in late 2019. The Sonnenschein and BAE batteries are 2V batteries connected in series, so each
battery bank is 48V. The Aquion batteries are 48V units connected in parallel. The C-10h
capacity is the capacity (Ah) of a battery that is drawn down over a 10-hour period. The battery
bank energy is calculated as kWh = capacity (Ah) x voltage (V) / 1000, and the useable energy
assumes the battery bank is drawn down by 30 percent before being recharged (70 percent in
the case of the Aquion batteries).
*Standard conditions for assessing solar panel performance are 1,000 W/m2 of solar radiation, 25C temperature, and
an air mass coefficient of 1.5.
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Figure 5. The eco-resort in September 2019. See Table 1 for details of solar panel arrays.
Table 1. LEI solar panel arrays, excluding 18 kW of stand-alone solar hot water units.
Solar panel array Specification Power
HSP. Hybrid solar power station (2008) 144 m2, 96 REC panels, 205W rating 20 kW
H. Near HSP (2019) 280 m2, 170 REC panels, 290W rating 50 kW
165 kW
In 2016, the eco-resort decided to move away from using lead acid batteries. They are not
environmentally friendly and must be fully charged regularly, which is difficult given that solar
power supply and the eco-resort’s power demand both fluctuate. The air temperature on Lady
Elliot Island is also often above the 20C optimum temperature for lead acid battery operation,
significantly reducing battery life. In 2016, the eco-resort trialled Aquion batteries which were
advertised as having none of these issues with more draw-down / recharge cycles, but they have
not performed well, and the supplier has now gone out of business, so unfortunately subsequent
purchases have continued to be lead acid batteries.
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Table 2. History of the LEI battery banks.
2008 Two battery banks installed, each with 24 Sonnenschein A602/3500 lead acid batteries.
2011 A third battery bank was installed using 24 BAE 24 PVV 4560 lead acid batteries.
2014 LEI selected the best 24 of the 48 Sonnenschein batteries. The eco-resort made one bank from these 24 batteries and replaced the other 24 with BAE 4560 batteries.
2016 A fourth battery bank was installed using 36 Aquion Energy S30P salt water batteries.
2018 A fifth battery bank was installed using 24 BAE 24 PVV 4560 lead acid batteries.
2019 Four more battery banks were installed, each using 24 BAE 24 PVV 4940 lead acid batteries.
Table 3. The nine battery banks of the eco-resort’s renewable energy system in 2019.
Battery
Capacity
C-10h Ah
No.
batteries
Bank
energy kWh
Useable
energy kWh
2008 Sonnenschein A602 3000 24 144 43
2011 BAE 24 PVV 4560 3470 24 167 50
2014 BAE 24 PVV 4560 3470 24 167 50
2016 Aquion S30P 40 36 69 50
2018 BAE 24 PVV 4560 3470 24 167 50
2019 BAE 26 PVV 4940 3650 24 175 52
BAE 26 PVV 4940 3650 24 175 52
BAE 26 PVV 4940 3650 24 175 52
BAE 26 PVV 4940 3650 24 175 52
1414 451
In Table 3 the useable energy assumes a 30 percent battery bank drawdown, which is close to
what happens every night as the batteries supply power to the eco-resort. The warranty
conditions actually require the batteries to be drawn down by no more than 20 percent of their
capacity, but it is too costly to operate the batteries with such a small draw down.
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6. Station operation
The eco-resort has a real-time power monitoring system. Figure 6 shows the power usage
overview display at noon on 28 October 2019 (the system can be used to examine the status of
each component of the HSP station). The solar panel arrays were generating 130 kW of power,
the eco-resort power demand was 50 kW and the multi-cluster box was directing the remaining
80 kW to charge the battery banks, which were at 83 percent capacity. The display shows that
the eco-resort used 831 kWh of energy in the previous 24 hours, generated entirely by the solar
panels. The generator had not been used at all.
Figure 6. The live power usage display. https://staff.ladyelliot.com.au/powerstation/
Figure 7 shows the monthly energy balance in October 2019 (top plot) and the power balance
for 13 October 2019 (bottom plot). Considering the monthly energy balance in October 2019:
• 24.7 MWh of energy was generated by the solar panels, with 13.5 MWh used by the eco-
resort and 11.3 MWh used to charge the battery banks.
• The eco-resort used 21.9 MWh of energy, with 13.5 MWh provided directly by the solar
panel arrays and 8.4 MWh provided by the battery banks.
• The daily solar energy production varied from 629 to 937 kWh and the average was 813
kWh.
• The daily eco-resort energy demand varied from 553 to 831 kWh and the average was 721